Hyperthermic Intraperitoneal Chemotherapy (HIPEC) is a specialized treatment for advanced cancers that have spread to the lining of the abdominal cavity, a condition known as peritoneal carcinomatosis. This complex procedure addresses microscopic disease often resistant to conventional intravenous chemotherapy. For select patients with colon cancer, this combined approach offers a potential pathway to extended survival where traditional treatments offer limited options.
Defining the Combined Procedure
The treatment is a two-phase process, beginning with extensive Cytoreductive Surgery (CRS) and immediately followed by the application of HIPEC. The initial surgical goal is to physically remove all visible tumor deposits from the abdomen, which can involve multiple organ resections and peritonectomy procedures. Surgeons meticulously strip away the peritoneal lining and remove any affected organs like the spleen, gallbladder, or parts of the small or large bowel to achieve complete removal of all macroscopic disease.
Once the visible tumors are removed, the HIPEC phase begins while the patient remains under general anesthesia. A chemotherapy solution is heated and circulated directly throughout the abdominal cavity using a specialized perfusion system, typically maintained between 41°C and 43°C to kill cancer cells while sparing healthy tissue. The chemotherapy circulates for a defined period, commonly ranging from 60 to 120 minutes, depending on the chosen drug and protocol.
Heating the chemotherapy enhances its effectiveness and allows it to penetrate superficial tissue layers more deeply than unheated drugs. The direct application delivers a high concentration of the drug directly to the site of the cancer, minimizing the systemic side effects typically associated with standard intravenous chemotherapy. This localized approach is designed to eradicate any microscopic cancer cells that may have remained after the surgical removal of visible tumors.
Patient Eligibility Criteria
The decision to proceed with this combined treatment depends on strict criteria, as not all patients with peritoneal spread of colon cancer are suitable candidates. A comprehensive assessment of the extent of the disease is performed using the Peritoneal Carcinomatosis Index (PCI) score. This scoring system divides the abdomen into 13 regions, assigning a score based on the size and distribution of the tumors, resulting in a maximum possible score of 39.
A high tumor burden, indicated by a high PCI score, generally excludes a patient from the procedure because the likelihood of achieving complete tumor removal is low. While thresholds vary, many centers consider a PCI score above 20 an exclusion criterion, and some even use a lower cutoff like 15 for optimal results. Furthermore, the tumor should be confined primarily to the abdomen, as the presence of significant extra-abdominal metastases, such as extensive disease in the liver or lungs, usually makes the patient ineligible.
The patient’s overall health status and physiological reserve are thoroughly evaluated using performance status scores. Because the procedure is physically demanding, patients must be in good health with minimal comorbidities to withstand the lengthy surgery and recovery. Factors like advanced age, poor heart or lung function, or a history of significant medical conditions can disqualify a patient, as they increase the risk of severe complications.
Navigating Surgical and Postoperative Risks
Cytoreductive surgery combined with HIPEC is one of the most extensive operations in surgical oncology and carries a high risk profile. The procedure can take between six and twelve hours to complete, requiring an extensive recovery, often including several days in an intensive care unit (ICU). Reported rates of overall postoperative complications, or morbidity, in specialized centers typically fall between 12% and 60% of patients.
Surgical complications include events like anastomotic leaks, where newly connected sections of the bowel fail to heal, requiring re-operation. Infection is another concern, with surgical site infections and sepsis being potential consequences of such an extensive abdominal procedure. Medical complications frequently occur, with kidney dysfunction and pulmonary issues like pleural effusions being commonly reported adverse events.
The procedure carries a risk of mortality, defined as the death rate within 30 or 90 days of the surgery. In high-volume, specialized centers, the mortality rate is typically reported between 0.9% and 5.8%. The risk of severe complications increases by approximately 3.5% for every single point increase in the Peritoneal Carcinomatosis Index score, demonstrating a direct correlation between the extent of the cancer and the danger of the operation.
Long-Term Survival and Quality of Life Outcomes
For carefully selected patients, the combination of CRS and HIPEC can lead to substantially extended survival compared to systemic chemotherapy alone. Achieving a complete cytoreduction (CC-0 or CC-1) is directly linked to the best long-term outcomes. The median overall survival (OS) for patients undergoing this therapy often ranges between 22 and 60 months, representing a doubling of survival time compared to historical control groups.
Five-year overall survival rates for patients with colorectal peritoneal metastases who undergo successful CRS/HIPEC are estimated to be between 19% and 35%. Patients with a low PCI score, particularly those with a score of 10 or less, demonstrate the most favorable prognosis, with some studies showing five-year survival rates exceeding 50% in this group. However, even with the extended survival, the disease recurrence rate remains high, with median progression-free survival (PFS) often reported between 9 and 16 months.
Patients typically experience a temporary decline in physical and functional well-being in the initial months following the complex surgery. Most patients who survive the initial postoperative period recover to their preoperative functional levels within three to six months. Studies suggest that patients who achieve long-term survival report a sustained or improved quality of life, demonstrating that the survival gain is not at the expense of long-term well-being.